The FSM requires proof of citizenship and presentation of a completed FSM Immigration Arrival and Departure Record for entry. A passport valid for at least 120 days beyond the date of entry into the FSM satisfies the first requirement.
For U.S. citizens and residents of U.S. possessions, an entry permit is issued on arrival, and there are no limitations on the length of stay as a result of the Compact of Free Association between the two countries. For nationals from some other countries, including South Korea, the Philippines, and several Central American nations, an automatic visa is issued upon arrival (duration varies from country to country).
Citizens of all other countries, including Australia, New Zealand, Japan, Taiwan, China, Brazil, and member states of the European Union, require a visa and must apply for it beforehand.
Pohnpei has no arrival fee, but it does have a departure fee of $20.00, which you must pay in cash before receiving your boarding pass.